The choice of food and the method of feeding bear so close a relation to age that it is necessary, in studying these questions, to regard them from the stand-point of the two stages of a child's life mentioned in the first chapter; that is to say, the periods of infancy and childhood.

Infancy. - An infant may be fed in one of three ways: 1, from the mother's breast; 2, from the breast of a foster-mother or wet-nurse; and, 3, from a bottle, by the method known as artificial or hand-feeding.